126 



ELECTRO-PHYSIOLOGY 



the tetanus is highly significant. This is expressed in the fact 

 that the height of the tetanus alters little with repeated excita- 

 tion in hydrophilus, while in dytiscus it rapidly decreases. 

 " Hydrophilus muscle, notwithstanding its excitation, remains 

 capable of functioning for so long that it only becomes exhausted 

 very gradually, provided it is given a short rest between the pro- 



kr-^\ 







! H -\ 



FIG. 59. Tetani, , of Dytiscus ; b, of Hydrophilus muscle at uniform excitation. (Rollett.) 



longed periods of activity in regular order of succession. Dytiscus 

 muscle, on the contrary, is exhausted by exertion in a compara- 

 tively short time, but if it is given longer rest between the 

 periods of exhaustive activity, it can, in spite of repeated efforts, 

 recover itself between times to a certain extent in the intervals." 

 Dissimilation and assimilation must accordingly take a different 

 course in the two kinds of muscle. Richet (I.e. p. 114) made 



